U.S. patent number 4,787,928 [Application Number 07/020,110] was granted by the patent office on 1988-11-29 for hydrated fibrous mats.
Invention is credited to Leslie L. Balassa.
United States Patent |
4,787,928 |
Balassa |
November 29, 1988 |
Hydrated fibrous mats
Abstract
Disclosed is a hydrated fibrous mass prepared by the steps
including introducing a source of cellulosic fibers to water with
continuous mixing until a ratio of water to fibers of about 50 to 1
is obtained and mixing the water and source of cellulosic fibers
until the source of cellulosic fibers has been comminuted to
substantially individual cellulose fibers. The mass can be
effectively used as a fire controlling agent. The mass can also be
used as a carrier for pesticides, and as a concrete or cement cure
rate controlling agent.
Inventors: |
Balassa; Leslie L. (Blooming
Grove, NY) |
Family
ID: |
26693038 |
Appl.
No.: |
07/020,110 |
Filed: |
April 24, 1987 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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744119 |
Jun 12, 1985 |
4665993 |
May 19, 1987 |
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Current U.S.
Class: |
71/23; 504/188;
504/358; 71/64.08; 71/64.09; 71/904 |
Current CPC
Class: |
A01N
25/10 (20130101); A62C 99/0009 (20130101); A62D
1/0007 (20130101); Y10S 71/904 (20130101) |
Current International
Class: |
A01N
25/10 (20060101); A62D 1/00 (20060101); A62C
39/00 (20060101); C05F 005/00 () |
Field of
Search: |
;71/1,11,23,27,DIG.1,64.08,64.09,903,904,3 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Lander; Ferris H.
Attorney, Agent or Firm: Darby & Darby
Parent Case Text
This is a division of application Ser. No. 744,119, filed June 12,
1985, now U.S. Pat. No. 4,665,993, May 19, 1987.
Claims
What is claimed is:
1. A method of applying an agricultural compound to a desired
location comprising the steps of:
preparing a hydrated fibrous mass by the steps including
introducing a source of cellulosic fibers to water with continuous
mixing until a ratio of water to fibers of about 50 to 1 is
obtained, and mixing the water and source of cellulosic fibers
until the source of cellulosic fibers has been comminuted to
substantially individual cellulose fibers, introducing a surfactant
to said mass, and introducing to said mass an agricultural
compound; selected from the group consisting of fertilizers,
herbicides and pesticides and
applying said mass containing said agricultural compound to a
desired location.
2. The method of claim 1 wherein said source of cellulosic fibers
is selected from the group consisting of newsprint, corn cobs, corn
stalks, straw, cane, dry leaves and cardboard.
3. The method of claim 1 wherein said mass further comprises a
viscosity enhancer selected from the group consisting of
methylcellulose, carboxymethylcellulose, sodium silicate, and
sodium alginate.
4. The method of claim 1 wherein said surfactant is selected from
the group consisting of glycerol monooleate, sodium lauryl sulfate
and lignin sulfonate.
5. The method of claim 1 wherein said surfactant is sodium lauryl
sulfate provided at 0.1 to 0.6% by weight of said mass.
Description
FIELD OF THE INVENTION
The present invention relates to the preparation and use of a
hydrated fibrous mass consisting of a slurry of cellulosic fibers
swollen with water. More particularly, the present invention
relates to the use of such a mass in firefighting, agricultural
applications and in other applications where it is desirable to
efficiently and economically apply large amounts of water to a
large surface area without rapid dissipation or evaporation.
BACKGROUND OF THE INVENTION
In firefighting, water has certain disadvantages which reduce its
efficacy in extinguishing fires. The primary effect of water on
fire is cooling, thereby reducing the ability of the fuel to burn,
and displacement of oxygen necessary for the combustion of fuel.
Unfortunately, water has a relatively high surface tension with
attendant poor wetting properties for many surfaces. Water also has
a low viscosity and flows well at any temperature between its
freezing and boiling points. When water is brought into contact
with very hot surfaces it has a tendency to bead and roll off the
surface. This phenomenon is caused by the formation of a layer of
steam between the surface and the water which acts to insulate the
water from direct contact with the hot surface, reducing the
ability of the water to absorb heat from the surface or displace
oxygen.
Additives can be introduced to water used for firefighting to
reduce the inherent disadvantages of water as a fire extinguishing
agent. Surfactants can be added to water to improve its wetting
properties. Gelling agents can be added to water to form a gel for
use as a firefighting agent. Such gels, however, lose cohesion and
viscosity on contact with hot surfaces. Foaming agents combined
with water can be quite effective in smothering fires under special
conditions. However, foams cannot be used in large fires since high
winds created by major fires dissipate the foam or prevent its
accurate application. In addition, in the case of chemical fires,
burning chemicals frequently cause the collapse of the foam and
consequent loss of most of its fire extinguishing properties.
OBJECT OF THE INVENTION
It is an object of the present invention to provide a hydrated mat
of fibers, capable of retaining large quantities of water for
application to large surface areas where it is desirable to
accurately direct large amounts of water economically and
efficiently and to retain water on the surface area without rapid
dissipation or evaporation.
SUMMARY OF THE INVENTION
It has now been unexpectedly discovered that a hydrated mass of
cellulosic fibers can be effectively used to extinguish fires and
especially wood burning conflagrations. A hydrated fibrous mass can
also be used as a carrier for pesticides and as a concrete or
cement cure rate controlling agent.
The hydrated mass is prepared by the steps including introducing a
source of cellulosic fibers to water with continuous mixing until a
ratio of water to fibers of about 50 to 1 is obtained, and mixing
the water and source of cellulosic fibers until the source of
cellulosic fibers has been comminuted to substantially individual
cellulose fibers.
DESCRIPTION OF THE INVENTION
The object of the invention is met by providing a hydrated mass of
fibers comprising water retained in a carrier of cellulosic fibers.
It is well known that cellulose fibers absorb several times their
weight in water and a mass of such fibers is capable of retaining
additional water immobilized by cohesion. A fibrous mat formed from
a mass of cellulose fibers and water forms an inexpensive,
nonflowing wet blanket.
Depending on the desired application, the characteristics of the
fibrous mass can be determined by the type of cellulose fibers
selected, the length of the fibers used, the pH of the water
retained by the fibrous mass, and by chemical additives to the
water which can enhance various characteristics of the hydrated
fibrous mass.
Any cellulosic fiber can be used as the carrier to form the fibrous
mass provided that the material must be capable of being shredded,
beaten or pulped into fibers which are capable of swelling in water
and forming a fibrous mat. Preferred fiber diameters are from 0.1
to 0.8 mm (millimeters). Preferred fiber length is from 2 to 10 mm.
Shredded newsprint is the preferred source of cellulosic fibers.
Newsprint is readily available in virtually unlimited quantities at
low cost and is bio-degradable and therefore ecologically
acceptable for use in fighting brush or grass fires for example, or
for use in agricultural applications. Other types of materials from
which cellulosic fibers can be obtained include wood pulp, shredded
corn cob, straw, leaves and other types of cellulosic biomass.
Well-known chemical additives can be introduced to water used in
forming the mass to assist in causing swelling of the cellulosic
fibers. Urea, sodium hydroxide and potassium hydroxide are examples
of such additives. Swelling is a function of the capacity of the
fiber to absorb water, but not all absorbing fibers will swell and
retain water. Nonabsorbing fibers do not retain water except for
retention due to cohesion.
FIG. 1 shows a flow diagram of the method of the present invention,
including the steps for preparing the hydrated fibrous mass, and
the application of the mass to an application surface.
In order to illustrate the present invention, reference is made to
the following examples which are not intended to limit the
invention in any respect.
EXAMPLE 1
A hydrated fibrous mass was prepared by introducing 1,000 ml
(milliliters) of water having a pH of 6 to a Vita Mix Model 3600
mixer from Vita-Mix Corp., Cleveland, Ohio. 55 grams of shredded
newsprint having 5% moisture content were introduced to the mixer
while the mixer was running at low speed (150 rpm) (revolutions per
minute). The newsprint was gradually introduced over a period of 5
minutes. After all of the newsprint had been added to the mixer,
the speed of the mixer was increased to about 3000 rpm. After five
minutes of mixing at 3000 rpm, a homogeneous non-flowing mass was
obtained. The viscosity of the mass was determined to be
approximately 500 cps (centipoise). On horizontal surfaces the
hydrated fibrous mat can be built up to a thickness of 4 to 6
centimeters. On vertical surfaces, the mat can be applied in
thicknesses of up to 0.5 to 1.0 centimeters.
Providing water with an alkaline pH aids in disintegrating the
newsprint into individual cellulose fibers. The hydrated fibrous
mass of Example 1 can be used to quickly extinguish brush or grass
fires, as well as industrial or structure fires, by blanketing the
area affected with the hydrated fibrous mass to form a fibrous mat
on the ground. Due to the density and viscosity of the fibrous
mass, the mass will remain in contact even with inclined surfaces
(such as burning trees). The fibrous mass can also be used to
prevent the spreading of a fire by covering forest floor litter and
brush.
An acidic pH is not preferred unless an acidic swelling agent such
as phosphoric acid (H.sub.3 PO.sub.4) is being used.
The hydrated fibrous mass of the present invention should not be
used to extinguish fires where water is contraindicated. Such fires
include electricity and machinery fires as well as certain types of
chemical fires.
The fibrous mass can be prepared ahead of time and then transported
to the scene of a fire. The mass can be stored in containers of
convenient size and weight. Paper or plastic bags of 25 to 100
pound capacity are acceptable. The prepared mass can then be
transported by air to the scene of a fire and then ejected from a
plane or other aircraft onto the fire. Alternatively, the mass can
be prepared from separate water and fibers onboard an aircraft, for
example, and then ejected onto a fire. Depending on fiber content,
the mass can be applied by spraying through nozzles (fiber content
of 2-5%), thrown by rotating throw wheels or dropped from the air
by plane or other aircraft (fiber content of 5-10%).
EXAMPLE 2
A hydrated fibrous mass of high viscosity was prepared by
introducing 1,000 liters of tap water at pH 5.5 to a Cowles-type
disperser (obtained from Myers Engineering, Bell, Calif.) having a
30 centimeter blade, a 20 horsepower motor, and a capacity of 1,000
liters. The water was introduced to the disperser and the mixer was
operated at 200 rpm. 100 kilograms of shredded newsprint having a
5% moisture content were added to the mixer as in Example 1, with
the disperser mixing at approximately 200 rpm. After the
introduction of the newsprint, the speed of the disperser was
increased to approximately 750-1000 rpm and mixing continued until
a homogeneous dispersion was obtained (after approximately 15
minutes).
The material obtained is non-flowing, having a viscosity of
approximately 1000 cps, and may be built up to about 10 centimeters
thickness on a horizontal surface. A hydrated mass of this
viscosity is of particular value in protecting buildings in city
fires, for example, by blanketing the roof of a building, thereby
preventing sparks and cinders being emitted from a burning building
from igniting adjacent buildings.
In certain applications it is desirable to provide the hydrated
mass with additives which act as fire retarding agents. For
example, in large-scale fires wherein high temperatures in excess
of 1500.degree. F. are encountered for more than one hour, the
hydrated mass may be heated for such a duration that the retained
water is evaporated, leaving dried cellulose fibers. To prevent
these fibers from becoming fuel for the fire sought to be
extinguished, flame retardant agents can be employed as adjuvants.
These agents may be dissolved in the water introduced to the mixer
prior to the addition of shredded newsprint or other sources of
cellulosic fibers. Flame retardant agents which can be used include
the following:
______________________________________ Tri-sodium phosphate 0.5 to
10% of dry fiber weight Borax 1.0 to 5% of dry fiber weight Urea
1.0 to 20% of dry fiber weight Sodium Silicate 5.0 to 20% of dry
fiber weight ______________________________________
These agents act to prevent the dried fibers from becoming a fuel
source by absorbing or adsorbing onto the fiber and causing the
fiber to char without flame and without forming glowing embers.
Anionic surfactants can be added to the hydrated fibrous mass to
increase the wetting properties of the mass. Suitable surfactants
for use in the invention include glyceryl monooleate, sodium lauryl
sulfate, and lignin sulfonate, among others. A preferred surfactant
is sodium lauryl sulfate added in an amount from about 0.1 to 0.6%
by weight of the dispersion. Higher proportions of surfactants such
as sodium lauryl sulfate are undesirable because incorporation of
air and foaming of the fiber dispersion will occur. Such foaming
will reduce the weight to volume ratio of the hydrated fibrous mass
reducing its overall effectiveness.
Additives can be introduced to the hydrated fibrous mass to
increase the viscosity and therefore the cohesion and clinging
properties of the hydrated fibrous mass. The following additives
are preferred for use in the present invention: Methylcellulose
added at 1.0 to 4.0% by weight of the dispersion;
carboxymethlycellulose added at between 1.0 to 4.0% by weight of
the dispersion; sodium silicate added at 3.0 to 15% by weight of
the dispersion; and sodium alginate added at 1.0 to 10% by weight
of the dispersion. These viscosity enhancers should be dissolved in
water (with mixing) before the addition of the cellulosic fiber
source.
Various bio-mass sources of cellulosic fibers can be used to
provide the hydrated fibrous mass of the present invention. Such
materials include corn cobs, corn stalks, straw, cane, dry leaves,
and cardboard. Urea (at 10-20% by weight of the dispersion) or
sodium hydroxide (at 5-15% by weight of the dispersion) can provide
the required degree of swelling. Depending on the cellulosic fiber
source, fiber swelling should be between about 10-200%.
In addition to serving as a useful firefighting aid, the hydrated
fibrous mass of the present invention can be used in agricultural
applications. The mass may be spread on to the soil surface at a
thickness necessary to supply moisture to the soil and to release
water over a period of time while keeping it near the surface. If
the material is to be applied to a dry, water-repellent surface,
the addition of a surfactant to the mass will overcome the initial
repellency of the soil surface. Suitable surfactants for use in the
invention include glyceryl monooleate, sodium lauryl sulfate and
lignin sulfonate, among others.
The hydrated mass of the present invention can also be used as a
carrier for fertilizers, herbicides or pesticides. The aerial
application of herbicides and pesticides can be made more efficient
by reducing loss through wind drift by incorporating the pesticides
or herbicides into the mass of the present invention and then
applying the mass to the desired location. The pesticides which can
be employed as adjuvants to the hydrated fiber mass include any
water soluble or water dispersible herbicide or insecticide such as
diazinone and ammonium sulfonate, among others.
The hydrated fibrous mass of the present invention can also be used
to control the rate of cure of fresh cement or concrete by applying
the mass to the surface of the fresh cement or concrete at a
desired thickness to form a hydrated mat. After the cement or
concrete has cured properly, the fibrous residue of the hydrated
mat can be easily removed by sweeping or vacuuming.
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